Apparatus for the treatment of dental caries

ABSTRACT

Apparatus for the treatment of dental caries includes a source of oxidizing gas and a handpiece for delivering the gas to a tooth. A cup attached to the handpiece is provided for receiving the gas and exposing a selected area of the tooth to the gas. The cup includes a resilient edge for sealably the edge for engaging the tooth around the selected area to prevent escape of a gas therepast.

The present application is a continuation of U.S. Ser. No. 10/246,105filed Sep. 18, 2002 now U.S. Pat. No. 6,743,016 which is a continuationof U.S. Ser. No. 09/712,611 now U.S. Pat. No. 6,454,566.

The present invention generally relates to the treatment of dentalcaries, and more particularly is directed to apparatus for the treatmentof dental caries utilizing an oxidizing gas.

The role of specific micro-organism such as, for example, streptococcusmutants in dental caries is well documented. Enzymes produced by suchmicro-organisms synthesize dextran from the sucrose passing through themonth with food or drink resulting in the formation of dental plaque anddental caries.

Dental caries is the decay of teeth caused by demineralization of theenamel surface with organic acids produced by bacteria which adhere toteeth surfaces.

Heretofore, dental caries have been removed through the use ofconventional grinding handpieces, lasers and air-blasting apparatus.However high-speed turbine drills or low-speed drills unfortunately willgrind both caries and sound dentine. Accordingly, a practitioner mustselect and grind only caries and consequently, this method depends uponthis skill of the practitioner. Lasers have been utilized to removecaries, however, not much success has been achieved for varies reasons.For example, blackened charred tissue blocks the laser radiation which,in turn, prevents the laser from reaching caries therebelow. Inaddition, heating also interrupts the ablation process.

With regard to air-blasting treatment of caries sound, dentine may alsobe easily removed, and accordingly, the skill of the practitioner is ofoutmost importance.

The present invention provides for the treatment of caries without thedisadvantages of the prior art hereinabove noted.

SUMMARY OF THE INVENTION

Apparatus for the treatment of dental caries in accordance with thepresent invention generally includes a source of oxidizing gas and ahandpiece for delivering the gas to a tooth. A cup attached to thehandpiece, is provided for receiving the gas and exposing a selectedarea of the tooth to the gas.

The cup may include a resilient edge for sealably engaging the tootharound the selected area to prevent escape of the gas therepast.Alternatively, a suitable sealant may be utilized for providing thesealed engagement between the cup and the tooth. This enables a totallyclosed system for the application of the gas to the tooth.

A source of oxidizing gas may include an ozone generator and an ozonepump. An aspiration pump may be provided, along with an aspiration lineconnected to the handpiece, for enabling circulation of the gas into andout of a cup chamber subtending the cup edge. In that regard acontroller may be provided for regulating the ozone and aspiration pumpsin order to circulate the gas into an out of the cup chamber at apressure insufficient to escape past the sealed engagement between andthe tooth.

The apparatus may further include a source of reductant, in fluidcommunication with the cup chamber and a reductant pump may be providedfor circulating the reductant through the cup chamber in order to flushthe oxidizing gas from the cup chamber and into the aspiration line.

A waste accumulator may be provided and connected to the aspiration linefor receiving the reductant. In addition, a filter may be provided forremoval of any residual oxidizing gas from the aspiration line.

In one embodiment of the present invention the cup edge includes arelatively uniform perimeter for sealably engaging a tooth between acusp and a gingiva. In another embodiment of the present invention, acup edge may include a contour enabling a sealably engagement withadjacent teeth. More specifically, the cupped edge may have a perimetercontoured for sealably engaging cusps of adjacent teeth.

BRIEF DESCRIPTION OF THE DRAWINGS

The advantages and features of the present invention will be betterunderstood by the following description when considered in conjunctionof the accompanying drawings, in which:

FIG. 1 illustrates a block diagram of apparatus for treatment of dentalcaries in accordance with the present invention, the apparatus generallyincludes a source of oxidizing gas, an aspiration pump, a source ofreductant, a reductant pump and a controller for providing the oxidizinggas to a handpiece;

FIG. 2 illustrated a handpiece in accordance with the present inventionfor delivering a gas to a tooth and generally showing a cup attached tothe handpiece for receiving the gas;

FIG. 3 illustrated the handpiece with an alternative cup embodiment, thealternative embodiment cup having an arcuate shape for facilitatingapplication of oxidizing gas to a tooth;

FIG. 4 is a diagram showing application of oxidizing gas to a toothbetween a cusp and a gingival utilizing the handpiece and cup shown inFIG. 3;

FIG. 5 is cross-sectional view of the cup shown in FIG. 2 that issuitable for use in the present invention;

FIG. 6 is a cross sectional view an alternative embodiment of a cup forexposing a selected area of a tooth oxidizing gas;

FIG. 7 is a cross sectional diagram showing an alternative embodiment ofa cup in accordance with the present invention for exposing adjacentteeth to oxidizing gas; and

FIG. 8 illustrates the use of the cup shown in FIG. 7 as it may beapplied to adjacent teeth.

DETAILED DESCRIPTION

With reference to FIGS. 1–4, there is shown apparatus 10 in accordancewith the present invention for the treatment of dental caries whichincludes a source 12 of oxidizing gas, preferably ozone, and a handpiece16 (see FIG. 2) for delivering the gas to a tooth, not shown in FIGS.1–3. The effectiveness of an oxidizing gas such as ozone is set forth inU.S. Pat. No. 6,409,508 entitled “Use of Ozone For The Preparation ofMedicaments For The Treatment of Dental Caries” by Edward Lynch. Thispatent is incorporated herewith in its entirety including allspecification and drawings by this specific reference thereto.

As illustrated in FIG. 1, the ozone source 12 includes an ozonegenerator 20 and an ozone pump 22 for supplying ozone through a line 24,a connector 28 and lines 30 to the handpiece 16. As used herein, theterm “ozone” is intended to embrace any suitable oxidizing gas, pureozone, ionized air and other ozone gaseous mixtures.

As noted in the referenced international patent application, ozone isdelivered at a pressures concentration and for a period of timesufficient to penetrate the carious tissue and kill substantial all ofthe micro-organism within a carious lesion. Specific examples of the useof ozone are set forth in the referenced patent application and areincorporated herewith by the specific reference thereto.

As shown in FIGS. 2–3, cups 34 36 attached to the handpiece 16 areprovided for receiving the gas and exposing a selected area 38 on atooth 40, see FIG. 3. The cup 34 may be attached to the handpiece 16 inany conventional manner and include a resilient edge, or sidewall, 44for sealable engaging the tooth 40 to prevent the escape of gastherepast.

Many different sized and shaped cups may be utilized, as for exampleshown in FIG. 3 the cup 36 includes an arcuate trunk 50 to facilitatethe placement of the cup 36 over the selected area 38 as shown in FIG.4. The cups 34, 36 may have relatively uniform perimeters 52, 54 forsealably engaging the tooth 40 between a cusp 58 and a gingiva 60 asshown in FIG. 4.

A further cup embodiment 64 is shown in cross-section in FIG. 6 includesa tapered sidewall 66 that may be used for application of oxidizing gasto a smaller selected area (not shown) on the tooth 40.

While a resilient edge or sidewall may be used to couple the cup to theselected area 38 on the tooth 40, it should be appreciated that aseparate sealant 68 (See FIG. 6) may be utilized for providing asealable engagement between the cup 64 and the tooth 40. In thisinstance, the sidewall 66 need not be resilient.

Another embodiment of a cup 70 is shown in cross-section in FIG. 7 whichincludes walls 72 which are contoured for enabling the sealableengagement with adjacent teeth 74, 76 as shown in FIG. 8. As shown inFIG. 8, a cup edge 80 has a perimeter contour 82 for providing asealable engagement with cups 86, 88 of adjacent teeth 74, 76.

All of the cups 34, 64, 70, cross-sectionally illustrated in FIGS. 5–7.include cup chambers 92, 94, 96 that subtend cup edges 98, 100, 102. Asshown each of the cups 34, 64, 70 include walls 44, 66, 72 that definethe chambers 92, 94, 96 and include first perimeters 106, 108, 110 forsealably coupling the walls 44,66, 72 to the handpiece 16. Secondperimeters 112, 114, 116 provide for coupling the walls 44,66 72 to thetooth 40 and exposing the selected areas 38 to gas circulated in thechambers 92, 94, 96.

As shown in FIG. 6, the embodiment 64 the first perimeter 108 may belarger than the second perimeter 115 or, as shown in FIG. 7, the firstperimeter 110 may be smaller than the second perimeter 116. Accordinglythis variation in cup 64, 70 design enables the application of oxidizinggas the any number of tooth contours and to the application of oxidizinggas to a plurality of teeth has hereinabove described.

With reference again to FIG. 1, the apparatus 12 includes an aspirationpump 120 and lines 30, 122, 124 connected to the handpiece 16 forenabling circulation of the ozone into and out of the cup chambers 92,94, 96.

A controller 126, which may be of any conventional circuit design, isprovided for regulating the ozone and aspiration pumps 22, 120 in orderto circulate the gas into and out of the cup chambers 92, 94, 96 at apressure insufficient to permit escape of the gas past a sealedengagement between the cups 34, 64, 70 and teeth 40, 86, 88. Control ofthe gas flows may also be effected through valves 127, 127 regulated bythe controller 126.

Additionally, the apparatus 10 may include a reductant source 128, whichis in fluid communication with the cup chambers 92, 94, 96 through lines30, 130 and a parastalic pump 131. The reductant, which may be asolution of thiocyanate or peppermint, is utilized to flush the cupchambers 92, 94, 96 of oxidizing gas. The oxidizing gas is flushed intothe aspiration line 122.

Any residual ozone is then aspirated from the accumulator 132 throughthe line 124 and into a canister 134 through line 136 for finalelimination of the ozone. Thus, the apparatus 12 provides for a totallyclosed system for the application and removal of ozone to and from teeth40, 86, 88.

It should also be appreciate that when the cups 34, 36, 64 are utilizedbetween teeth 40, 138 (not shown in FIG. 4) a separate dam 140 maybeutilized as necessary to enable the cups 34, 36, 64 (not shown in FIG.4) to sealably enclose a selected area for treatment between the teeth40, 138.

EXAMPLE 1 Ozone Detection (ppm) Around the Cup Using a Ozone Analyserafter Either 10 or 20 s of Ozone Application In Vivo

Study or Test: Ozone detection (ppm) around the cup 34 using a ozoneanalyser after either 10 or 20 s of ozone application in vivo.

Purpose: To assess the maximum ozone detectable level (ppm) around thecup 34 after either 10 s or 20 s of ozone application in vivo.

Study or Test Protocol: 20 primary root carious lesions (PRCLs) wererandomly selected when the cross-sectional study was conducted. The tipof the sensor was always held within 2 mm of the edge of the cup,positioned half way between the mesial and occlusal sides of the cup.The maximum ozone detectable level (ppm) around the cup from theextracted teeth using an ozone analyser after 10 s of ozone application.The ozone analyser used was an API 450 model available from ENVIROTechnologys, UK, and was calibrated by the supplier within the previousweek of delivery and this device was not used for any other purposeother than this study in the interim.

Overlying plaque was then removed using a hand held standard fine nylonfibre sterile toothbrush with water as a lubricant. Each tooth was driedusing dry sterile cotton wool rolls and a dental 3 in 1-air syringe. Theexcavator blade was used to traverse the lesion in line with long axisof the tooth across the maximum gingival/occlusal dimension. Half ofeach lesion was removed using a sterile excavator. Subsequently, theremaining lesion was exposed to the ozone gas for a period of either 10s or 20 s at room temperature (23° C.) and maximum detectable ozonelevel was also measured using this ozone analyser.

Test Results:

The maximum ozone detectable level (ppm) around the cup from lesions fora period of either 10 s (Table 1 and FIG. 1) or 20 s (Table 2 and FIG.2) ozone application during the treatment of root carious lesions wereas follows:

TABLE 1 Maximum ozone detectable level (ppm) after a 10 s of ozoneapplication Ozone detection Teeth types Sites (10 s) Upper left incisorMesial 0.066 Upper right 1. premolar Buccal 0.001 Upper right canineDistal 0.002 Upper right 1. molar Buccal 0.006 Upper left 2. premolarBuccal 0.076 Lower right 2. premolar Mesial 0.058 Lower left 1. premolarBuccal 0.169 Lower left lateral Buccal 0.106 Upper right lateral Distal0.001 Lower left canine Labial 0.147

TABLE 2 Maximum ozone detectable level (ppm) after a 20 s of ozoneapplication Ozone detection Teeth types Sites (20 s) Lower left lateralLabial 0.137 Lower left 1. premolar Buccal 0.177 Lower right incisorLabial 0.069 Upper right canine Labial 0.033 Upper right lateral Labial0.079 Lower left 2. premolar Buccal 0.002 Lower right 1. molar Buccal0.083 Upper left lateral Labial 0.004 Lower left canine Labial 0.056Upper left 1. premolar Mesial 0.001

Conclusion: The use of a cup is a safe way of delivering ozone whenozone was applied for a period of either 10 s or 20 s on the rootcarious lesions.

EXAMPLE 2 Assessment of Maximum Ozone Levels from Extracted Teeth afterthe Use of Ozone for 10 s.—An In Vitro Test Report

Study or Test: Assessment of the maximum detectable ozone levels,detected adjacent to the cup, from extracted teeth after the use ofozone for 10 s in vitro.

Purpose: To assess the maximum ozone detectable level (ppm) around a cupfrom the extracted teeth after a 10 s application of ozone.

1. Study or Test Protocol: 14 extracted teeth were selected. The tip ofthe sensor was always held within 2 mm of the edge of the cup,positioned half way between the mesial and occlusal sides of the cup.The maximum ozone detectable level (ppm) around the cup from theextracted teeth using an ozone analyser was recorded during 10 s ofozone application with the generator setting on maximum at level 10. Theozone analyser used was the API 450 model and this was calibrated by thesupplier within the previous week of delivery. This device was not usedfor any other purpose other than this study in the interim.

The Ozone Delivery System

After plaque removal with 2 sterile cotton wool rolls, ozone gas wasdelivered onto the surface of each primary root carious lesion in eachextracted tooth for 10 s after the lesion was dried for three secondswith a standard three in one dental syringe.

Test Results:

The maximum ozone detectable level (ppm) around the cup from theextracted teeth after a 10 s application of ozone during the treatmentof root carious lesions were as shown in Table 3.

TABLE 3 Maximum ozone detectable level (ppm) Teeth types Sites Ozonedetection Upper incisor Mesial 0.005 Upper lateral incisor Labial 0.004Upper canine Labial 0.003 Upper 1. premolar Mesial 0.006 Upper 2.premolar Distal 0.002 Upper 1. molar Buccal 0.003 Upper 2. molar Mesial0 Lower incisor Lingual 0.007 Lower lateral incisor Distal 0.001 Lowercanine Mesial 0 Lower 1. premolar Distal 0.009 Lower 2. premolar Lingual0.018 Lower 1. molar Lingual 0.016 Lower 2. molar Mesial 0.005

Conclusion: The use of a cup is a safe way of delivering ozone whenozone was applied for a period of 10 s on the root carious lesions onextracted teeth.

EXAMPLE 3 Measurement of Ozone from the Handpiece

The handpiece 16 from the ozone generator 20 was attached directly tothe inlet pipe a Mini-HiCon™ the ozone detector (not shown).

Peak readings from Mini-HiCon ™ (g/Nm³) Duration Reading 1 Reading 2Reading 3 Reading 4 Reading 5 Reading 6 Average (seconds) (g/Nm³)(g/Nm³) (g/Nm³) (g/Nm³) (g/Nm³) (g/Nm³) (g/Nm³)  5 5.4 5.3 5.4 4.3 5.25.2 5.1 10 4.7 4.8 4.6 3.5 4.4 4.5 4.4 20 4.9 5.9 6.3 6.3 5.9 30 6.3 6.56.3 6.6 6.4 60 6.6 7.0 7.0 6.7 6.8

Peak readings from Mini-HiCon ™ (ppm) Duration Reading 1 Reading 2Reading 3 Reading 4 Reading 5 Reading 6 Average (seconds) (ppm) (ppm)(ppm) (ppm) (ppm) (ppm) (ppm)  5 2522 2475 2522 2008 2428 2428 2397 102195 2242 2148 1635 2055 2102 2063 20 2288 2755 2942 2942 2732 30 29423036 2942 3082 3000 60 3082 3269 3269 3129 3187

The peak reading was obtained after about 8 seconds (even when thegenerator was switched on for only 5 seconds) and perhaps represented an“overshoot” before the generator/detector combination stabilized forthe >20 second durations. The level then remained fairly constant atbetween 3.6 and 4.7 g/Nm³.

To convert from g/m³ to ppm:

The formular weight of ozone is 48 g and therefore 1 g of ozone is1/48th of a mole. The molar volume of an ideal gas (at standardtemperature and pressure) is 0.0224138 m³/mol. 0.0224138/48=467×10⁻⁶ m³.Therefore 1 g/m³ of ozone in air is 467 ppm. (The ozone detector givesreadings as g/Nm³ which is “normalized” to standard temperature andpressure).

Measurement of the Ozone Dissolving in a Potassium Iodide Solution

Ozone was passed through the handpiece 16, immersed in 100 ml of a 20 mMpotassium iodide solution in a 250 ml conical flask covered withparafilm for the stated durations. The handpiece was then removed andthe flask sealed with a neoprene bung and shaken vigorously. A 1.50 mlaliquot was removed and its electronic absorption spectrum acquired.(These measurements were taken before a diffuser was fitted.) Thegenerator settings were:—air=1, O₃=1, vac=0, red=0,regulator-setting=10.

λ_(max) λ_(max) λ_(max) (351 nm) Duration (351 nm) (351 nm) λ_(max) (351nm) average (seconds) absorbance absorbance absorbance absorbance 1 0.060.08 0.11 0.08 2 0.50 0.44 0.26 0.40 3 0.70 0.56 0.42 0.56 4 0.77 0.690.50 0.65 5 0.90 0.84 0.51 0.75 6 1.08 0.99 0.68 0.92 7 1.17 1.11 0.751.01 8 1.30 1.27 0.95 1.17 9 1.40 1.40 1.19 1.33 10 1.57 1.43 1.38 1.46To Calculate the Concentration from the Peak Absorbance:A=E×C×Lwhere

-   -   L=cell path length (1 cm)    -   C=concentration (mol)    -   E=extinction coefficient    -   A=absorbance        E for 1M=2.97×10⁴        E for 1 μM=0.0297        C=A÷E        concentration in μmol/l is absorbance/0.0297

Total Volume of Ozone λ_(max) dissolved air/ozone in air Ozone Durationabsorbance Concentration ozone Ozone mixture (μg/ml = in air (seconds)(average of 3) (μmol/l) (μmol) (μg) (ml) g/m³) (ppm) 1 0.08 2.69 0.26913 8 1.625  759 2 0.40 13.47 1.347 65 16 4.063 1897 3 0.50 18.86 1.88691 24 3.792 1771 4 0.65 21.89 2.189 105 32 3.281 1532 5 0.75 25.25 2.525121 40 3.025 1413 6 0.92 30.98 3.098 149 48 3.104 1450 7 1.01 34.393.439 165 56 2.946 1376 8 1.17 39.39 3.939 189 64 2.953 1379 9 1.3344.79 4.479 215 72 2.986 1394 10 1.46 49.16 4.916 236 80 2.950 1378NMR Analysis of Plaque/Caries

1. Plaque samples were obtained from volunteers and each sample wasdivided into two. Half of each sample was treated with ozone and halfleft untreated as a control.

2. The samples were each weighed. Then 600 μl of 0.5 M HClO₄ was addedto each sample and rotamixed.

3. The samples were centrifuged and supernatants retained.

4. The samples were neutralized to a pH of between 6 and 8 and thevolume of KOH used was noted.

5. The samples were centrifuged again and 600 μl of supernatant weretaken for analysis.

6. 70 μl of D₂O and 30 μl of sodium3-trimethylsilyl-(2,2,3,3,-²H₄)-propionate (5 mM in D₂O) were addedprior to NMR analysis.

NMR Analysis of Saliva

1. Saliva samples were obtained from volunteers and each sample wasdivided into two. Half of each sample was treated with ozone and halfleft untreated as a control.

2. The samples were centrifuged and supernatants retained.

3. 70 μl of D₂O and 30 μl of sodium3-trimethylsilyl-(2,2,3,3,-²H₄)-propionate (5 mM in D₂O) were addedprior to NMR analysis.

Iodine Standards (in 20 mM Potassium Iodide)

Iodine Concentration 351 nm Absorbance at 4 uM 0.1144 5 uM 0.1410 7 uM0.1690 10 uM  0.2002

Although there has been hereinabove described apparatus for thetreatment of dental caries in accordance with the present invention forthe purpose of illustrating the manner in which the invention may beused to advantage, it will be appreciated that the invention is notlimited thereto. Accordingly, any and all modifications, variations orequivalent arrangements which may occur to those skilled in the art,should be considered to be within the scope of the invention as definedin the appended claims.

1. Dental apparatus comprising: a source of ozone gas; a gas deliveringhandpiece interconnected with said source of ozone gas; a gas receivingcup attached to said handpiece, said cup including at least one sidewallfor directing the received gas onto a selected area of the tooth; meansfor enabling circulation of the gas into and out of the cup for a periodof time sufficient to penetrate tissue and kill substantially all of themicro-organisms within a carious lesion; and a resilient edge formed onsaid sidewall for sealably engaging the sidewall around the selectedarea.
 2. Dental apparatus comprising: a source of ozone gas includes anozone pump; a gas delivering handpiece interconnected with said sourceof ozone gas; a gas receiving cup attached to said handpiece, said cupincluding means for directing the received gas onto a selected area ofthe tooth; and means for enabling circulation of the gas into and out ofthe cup, including an aspiration pump and aspiration line, for a periodof time sufficient to penetrate tissue and kill substantially all of themicro-organisms within a carious lesion.
 3. The apparatus according toclaim 2 further comprising a controller for regulating the ozone andaspiration pumps in order to circulate the gas into and out of the cup.4. The apparatus according to claim 2 further comprising a source ofreductant in fluid communication with the cup.
 5. The apparatusaccording to claim 4 further comprising a reductant pump for circulatingthe reductant through the cup and into said aspiration line.
 6. Theapparatus according to claim 5 further comprising a waste accumulatorconnected to said aspiration line for receiving the reductant.
 7. Theapparatus according to claim 6 further comprising a filter for removalof any residual oxidizing gas from the aspiration line.